[An unrecognized cause of dyspnoea].

BACKGROUND: Neuralgic amyotrophy is characterised by pain in the neck or shoulder region, followed by neuropathy of both motor and sensory nerves of the brachial plexus. The incidence of this condition is estimated at 1/1000 per year. In a rare variant of the syndrome, involvement of both phrenic nerves can occur, leading to diaphragmatic paralysis and severe orthopnoea.

CASE DESCRIPTION: A 67-year-old woman was referred to us with acute orthopnoea. Imaging studies showed bilateral diaphragmatic paralysis, and electromyography (EMG) confirmed neuropathy of both phrenic nerves. The diagnosis was bilateral neuralgic amyotrophy. The patient received nocturnal ventilation support via nasal high flow oxygen therapy. This symptomatic treatment had a positive effect.

CONCLUSION: Isolated phrenic nerve neuropathy is a rare variant of neuralgic amyotrophy, leading to orthopnoea. Recovery is slow and frequently incomplete. Supportive treatment with non-invasive ventilation support is necessary to improve the patient's quality of life.